At present, to resolve problems of migration, a lot of supported combinations, and the like of a virtual machine (VM), caused by virtualization of a server in a data center, a Network Virtualization Overlay (NVO) technology applied to a data center network emerges at the right moment.
Due to an application of the network virtualization overlay technology, a lot of virtual machines may be deployed in the data center. However, a lot of host routes may be generated in each router during a process of migrating a current virtual machine across the data center. If a lot of virtual machines are migrated, the number of routes in a router may increase. Therefore, when a packet is forwarded to a migrated VM, a plurality of times of route matching needs to be performed to identify a correct route corresponding to the VM for forwarding the packet. In this case, the speed of forwarding the packet by a router is reduced, and forwarding efficiency of the router is also reduced.